An 18-year-old man with a gun allegedly tried to rob
a clerk at a convenience store in the 8100-block of South Racine Avenue just
after 7:55 p.m.

Police said that's when the security guard stepped
in and shot the teen several times. The suspect got away, leaving his gun
behind at the scene.

Chicago Police Superintendent Eddie Johnson said it
didn't take long for officers to figure out what happened.

"He did run. He ran and went home and the
people inside called the police to say he'd been shot. But we were able to
match up his story with the story that happened over here so he was placed in
custody," Johnson said.

The suspect was taken to the Advocate Christ Medical
Center, where he was listed in critical condition.